Currently I’m using Shimano Compact chainring 50/34T. I intend to change the bigger one to 53 or 54T while retaining the small one. I was told by the bike shop the difference between the 2 chainring shld not be more than 16T (50-34). If change to 53/54, the difference will be 19/20T. Will there be any abrupt problem for the chain to roll over?
Technical question on bigger chainring
- Thread starter novetan
- Start date
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cyberknight
As long as I breathe, I attack.
- Location
- Land of confusion
You could get chain drop when changing to the small ring but a chain catcher could help out with that , i think assuming you want to keep the same BB and small inner ring the max you can go to with a comapct chainring is a 52 .
Is there any reason why you need a bigger ring? i was on thefront of the club run yesterday and was riding at 25 mph on a 50 and mid block on the back so no more than a 50x 15 .Maxxed out down hill at about 40 mph once as i could not spin much faster.
Is there any reason why you need a bigger ring? i was on thefront of the club run yesterday and was riding at 25 mph on a 50 and mid block on the back so no more than a 50x 15 .Maxxed out down hill at about 40 mph once as i could not spin much faster.
Cyclopathic
Veteran
- Location
- Leicester.
Could it perhaps cause a problem with the amount of slack the rear mech arm is able to take up?
Rob3rt
Man or Moose!
- Location
- Manchester
Yes, the large drop from large big ring to small inner chain ring, will mean a lot of slack needing to be taken up. Some rear mech's just won't like this!
Both true. If you can spin out a 50x12 on the flat, then you should be riding in the Tour. How much time do you actually spend in your big ring/small cog combination to make it worth compromising the ability to shift chainrings?
400bhp
Guru
Why?
HLaB
Marie Attoinette Fan
What size of cassette have you got on the back novetan, if its a 12t you could easily change to an 11t to stop you spinning out downhill and if you still want to go to a larger ring consider a 38/52 (still compact sized, so cheaper) and get a larger cassette to retain the smaller gears.
My rear is 12-27T. I must admit I havent spin out yet. Just toying with the idea of a bigger chainring esp when downhill I'm running out of gears. But I'm not too sure will the bigger chainring helps. What's your take?
as 400bhp. Why?
I use a 53/39 12/21, Susie uses a 50/34 12/25, but that's because we're different animals. We both get around ok. If you' were to start spinning out then you could go to a 53/39 or a 52/38, but, to be honest, it won't make that much of a difference. If you can do without the lower ratios getting rid of the 34 will give you more choice in the midrange, which isn't a bad thing. Then again, if you were looking for a smoother ride you might go to a 12/23 at the back.
I use a 53/39 12/21, Susie uses a 50/34 12/25, but that's because we're different animals. We both get around ok. If you' were to start spinning out then you could go to a 53/39 or a 52/38, but, to be honest, it won't make that much of a difference. If you can do without the lower ratios getting rid of the 34 will give you more choice in the midrange, which isn't a bad thing. Then again, if you were looking for a smoother ride you might go to a 12/23 at the back.
Rob3rt
Man or Moose!
- Location
- Manchester
So he can look like a big man with a massive chainring, but behind it, he has a hidden pussy gear that no-one will notice
black'n'yellow
Guest
No benefit, so don't bother. If you are spinning out 50/12 downhill then you are probably hitting 40+mph - in which case, stop pedalling and tuck in.
400bhp
Guru
Cyclopathic
Veteran
- Location
- Leicester.
Eloquently put.
HLaB
Marie Attoinette Fan
If your not spinning out leave it be just now and when the cassette naturally wears out change it for something with an 11t; unless you particularly feel you want to make hills harder try for something still with a 27t. Changing chainrings with too large a gap will only cause problems. FWIW, I like SRAM cassettes they usually do the ratios I want; I'm currently running a Sram 11-26, one more at either end than the 12-25 Shimano cassette the bike came with. IIRC in theory the bike tops out over 40mph compared to under 40mph before and it climbs better than before.
